Polypropylene (PP) compositions mainly composed of polypropylene, in which ethylene-propylene-based rubbers, inorganic fillers and the like are blended, have excellent rigidity and impact resistance and have high moldability, and therefore have been widely used for interior and exterior parts of automobiles or the like. They have also been used for air-bag pads (hereinafter also referred to as AB pads) of automobiles, and characteristics such as fluidity and impact resistance at low temperature are required therefor. In the polypropylene compositions, however, it is generally difficult to achieve both of the rigidity and the low-temperature impact resistance at the same time, and under the present circumstances, one of the characteristics cannot help being sacrificed to some extent.
In Patent Document 1, there is disclosed a polypropylene composition having a structure comprising polypropylene as a matrix phase and an elastomer as a dispersion phase, in which polyethylene is present in the dispersion phase, in order to obtain a balance between the rigidity and the low-temperature impact resistance. However, this compounding system is difficult to be applicable to a molded article particularly requiring fluidity (for example, an AB pad required to have a thick portion and a thin portion).
In Patent Document 2, there is disclosed a composition comprising PP composition comprising polypropylene, low-density polyethylene, an ethylene-olefin copolymer rubber and the like, and a peroxide blended in the PP composition in a predetermined amount, as a material for an AB pad having a thick portion and a thin portion. However, this compounding system is difficult to achieve a balance between the rigidity and the low-temperature impact resistance.    Patent Document 1: JP-A-11-130923    Patent Document 2: JP-A-2001-62861